Arctic ground squirrel

The Arctic ground squirrel (Urocitellus parryii) is a species of ground squirrel native to the Arctic. People in Alaska, particularly around the Aleutians, refer to them as "Parka" (pronounced "par'kee") squirrels. probably because their pelt is good for making the fur edging on the hoods of Parka style jackets. [2]

During hibernation, its brain drops to just above freezing, its core body temperature reaches temperatures down to -2.9°C[7] and its heart rate drops to ~1BPM. Peripheral, colonic, and blood temperatures become subzero by means of supercooling.

Habitat

Physical description

The Arctic ground squirrel has a beige and tan coat with a white-spotted back. This squirrel has a short face, small ears, a dark tail and white markings around its eyes. Arctic ground squirrels undergo a coat change from summer to winter. Summer coats include red/yellow colorations along the checks and sides of the animal. In fall, these red patches are replaced with silvery fur. The average length of an Arctic ground squirrel is approximately 39 cm (15 in). Since arctic ground squirrels undergo drastic seasonal changes in body mass it is difficult[9] to give an average mass, but for adult females it is close to 750 g (26 oz), however, males generally are around 100 g (3.5 oz) heavier than females.[8]

Reproduction

Arctic ground squirrels live individually in burrow systems. Mating occurs between mid-April and mid-May (depending on latitude) after winter hibernation. Mating includes male-male competition for access to females, and litters are typically sired by multiple males. Gestation is approximately 25 days, and results in a litter of 5 to 10, 10 g (0.35 oz) hairless pups. After 6 weeks the pups are weaned and this is followed by rapid growth to prepare for the upcoming winter.[8]

Behaviour

The Arctic ground squirrel hibernates over winter from early August to late April in adult females and from late September to early April for adult males,[10] at which time it can reduce its body temperatures from 37 °C(99 °F) to as little as −3 °C(27 °F).[11] In the warmer months, the squirrel is active during the day time.

During the mating season, males engage in male-male aggressive encounters for the mating rights.[12]

Communication between squirrels is done through both vocal and physical means. When they meet, nose to nose contact is made or other body parts are pressed together. The "tsik-tsik" calls are made in response to threats and vary as between different predators. Deep guttural sounds are used to indicate land-based predators while short "band whistle" chatter indicates danger from the air.[8]

Food habits

This squirrel feeds on grasses, sedges, mushrooms, bog rushes, bilberries, willows, roots, stalks, leaves, flowers, and seeds. Sometimes this squirrel carries food back to its den in its cheeks.[8]